(a) Field of the Invention
The present invention relates to an improvement of a quick-return mirror driving mechanism for single-lens reflex cameras.
(b) Description of the Prior Art
Generally, as a quick-return mirror driving mechanism equipped in a conventional single-lens reflex camera, such a type of mechanism wherein a mirror-up is effected by releasing a mirror-up operating member through a mechanical or electromagnetic means and a mirror-down is effected by a mirror-down operating member to be released by a mechanical means when the opening and closing movement of shutter blades has been completed is popular. In case of this type, it is necessary that the mechanical means are provided with sufficinetly large power and operating stroke to guarantee a proper operation. This requirement introduces such inconveniences as to make the design of driving mechanism difficult and the connection between a shutter mechanism and mirror driving mechanism troublesome at assemblage.
To delete this defect, a quick-return mirror driving mechanism of a type wherein the mirror-up operating member and mirror-down operating member are released by electromagnetic means respectively independent has been proposed, but this type of mechanism has such a defect that the mechanism becomes complicated and the manufacturing cost increases because it is necessary to prepare two sets of electromagnetic device and mechanical device related thereto.